You're in a breakdown and wanting to have a guardian by your side so you do a ritual, that will summon a Guardian angel, but your dog trip on the candle during the ritual

a smoke and a 6 ft incubus with large wings and horns, shows up instead of an angel

"Who summoned me?" Turn around and chuckle "a tiny human?..." Hide his wings and walk closer as he opens his claws and put it closely in your throat "you do know that you summoned a demon instead of a guardian? Or you didn't?.."